In general, hydraulic excavators as construction machines include a small-sized hydraulic excavator called a mini excavator suitable for a work on a small work site, and this small-sized hydraulic excavator is formed having a small upper revolving structure so as to be suitable for running and works on a small site.
Here, the small-sized hydraulic excavator is composed of an automotive lower traveling structure, the upper revolving structure rotatably mounted on the lower traveling structure and having a cab provided on a revolving frame forming a support structural body, and a working mechanism provided on the front side in a front-rear direction of the upper revolving structure capable of moving upward/downward.
On the other hand, the cab of the hydraulic excavator has five pillars provided extending in the vertical direction while being located on the left front, right front, left intermediate, left rear, and right rear and the cab has a cab box in which a space between each pillar is covered by a front surface, a left front side surface, a left rear side surface, a right side surface, a rear surface, and a top surface and the inside becomes an operator's room. In this cab box, a door is provided having a rear end portion rotatable in the front-rear direction by using the left intermediate pillar as a fulcrum in order to open/close an entrance way between the left front pillar and the left intermediate pillar.
Moreover, an engaging member is mounted on the rear surface portion of the left front pillar. This engaging member is composed of a mounting plate mounted on an intermediate portion in a height direction of the rear surface portion and a substantially U-shaped engaging ring provided protruding rearward from the mounting plate. Here, the engaging member is mounted on the left front pillar by screwing the mounting plate with the rear surface portion.
In this case, a door holding member engaged with the engaging ring and holding the door at a closed position is provided on the front end side of the door corresponding to the engaging member when the door is rotationally moved in a closing direction (Patent Document 1).